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  • 8/10/2019 Motorbicycle building

    1/166

    or

    440

    H68

    ding

  • 8/10/2019 Motorbicycle building

    2/166

    c

    used

    Whit

    Emb

    Boo

    HON.

    C

    write

    Forn

    Tick.

    Wo-

    in.

    inside

    at the end. The diameter

    of

    the

    prints

    at the

    other

    two

    ends

    is

    l

    y

    L

    in. and

    l-j

    3

    ^-

    in.

    by

    i

    in.

    long.

    If

    it

    is decided

    to

    do with-

    out

    core-boxes

    for

    these two

    patterns,

    the

    larger

    part

    will have to be

    plain-cored

    right through

    l

    T

    3

    ^in.,

    leaving

    the recessed

    portion

    for

    the

    ball-

    race

    to be machined

    out of

    the

    casting.

    The

    diameter

    of

    the

    print

    for the

    lg-in.

    tubes is the

    same as

    for

    the

    core-boxes,

    but

    the

    length

    is

    differ-

    ent.

    The

    core

    being

    supported

    in

    the

    mould

    at

  • 8/10/2019 Motorbicycle building

    27/166

    PATTERNS FOR FRAME

    CASTINGS.

    25

    one end

    only,

    the

    print

    must be

    longer

    on the

    pattern

    than

    the

    depth

    to

    be

    cored. Thus the

    pvint

    for

    the

    top

    head

    lug

    should

    be

    l\

    in.

    long,

    //and

    that

    for the bottom

    1|

    in.

    long.

    //

    Seat

    Lug.

    The seat

    lug (Fig. 17)

    is made

    from

    /

    two

    turned

    parts;

    the rear

    part,

    to

    take

    the

    f-in.

    bolt,

    is

    cut

    out

    by

    hand,

    similar in

    shape

    to

    Fig.

    18,

    and

    glued

    and

    pegged

    on.

    Turn

    the

    centre

    part

    for

    the

    down

    tube 1

    T

    5

    ^

    in.

    in

    diameter

    in

    the

    centre,

    tapering

    to

    1

    -^

    in.

    at

    each

    end

    by

    If

    in.

    long,

    the

    print

    standing

    out

    i

    in. at

    each

    end

    by

    l

    T

    V-in.

    in

    diameter.

    The

    front

    portion

    for

    the

    top

    tube

    is

    ly\-

    in. in

    diameter at

    the

    extreme

    Fig.

    19.

    Lower

    Horizontal

    Lug.

    edge,

    tapering

    up

    at

    about

    3

    degrees

    of

    taper.

    The

    core-print

    for

    this

    member is

    1

    T\

    in.

    in

    diameter

    by

    If

    in.

    long.

    The

    rear

    part

    is

    cored out

    f

    in.,

    as shown

    by

    the

    dotted lines

    in

    Fig.

    18,

    and will

    require

    a

    print

    of

    this

    diameter,

    standing

    out

    i

    in.

    at

    each end.

    Lower

    Horizontal

    Lugs.

    The

    patterns

    for the

    two

    lower

    horizontal

    lugs

    (Fig.

    19)

    are alike

    except

    in

    the

    angle,

    the one

    shown

    being

    69

    de-

    grees

    and

    the

    other

    57

    degrees. They

    are

    made

    from

    two

    turned

    parts,

    and

    each member

    is

    to

    take

    lg-in.

    tube.

    The

    parts

    are

    exactly

    as

    the

    main

    parts

    of the

    seat

    lug,

    the

    only

    difference

  • 8/10/2019 Motorbicycle building

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    26

    MOTOR

    BICYCLE

    BUILDING.

    being

    the

    absence

    of

    the rear

    ears

    and

    the

    different

    angle

    of

    the front

    lug

    that

    is,

    57

    degrees.

    The

    same

    remarks

    apply

    with

    regard

    to

    the core-

    prints.

    Girder Tube

    Lugs. Figs.

    20 and 21

    are

    side

    and

    top

    views

    of one of

    the

    girder

    tube

    lugs.

    A

    pair

    of

    these

    will

    be

    required,

    but the

    difference

    is

    so

    slight

    that one

    pattern may

    be used

    for

    both.

    This

    pattern

    should

    be

    made

    with

    the

    grain

    of

    the wood

    running

    with

    the

    length

    of the

    pattern,

    and the

    prints glued

    and

    pegged

    on

    each side.

    The

    drawings give

    all

    dimensions,

    which are

    Figs.

    20 and 21.

    Girder

    Tube

    Lujrs.

    finished

    sizes of the

    machined

    casting,

    so

    due

    allowance

    must

    be

    made for

    machining.

    The

    core

    and

    print

    for

    the oval

    part

    should

    be made as

    near the finished size as

    possible,

    as

    this

    has to

    be

    filed out in

    the

    casting.

    It

    will

    be

    necessary

    to

    have

    a core-box for the

    oval

    part

    ;

    a

    piece

    of

    fork

    tube

    of this size and section

    will

    answer

    ad-

    mirably.

    The

    length

    of

    prints

    for

    both

    oval

    and

    round

    holes need be

    only

    J

    in. from each

    side

    of

    the

    pattern.

    Front Fork

    Crown.

    The

    pattern

    for

    the

    front

    fork crown is

    shown

    in

    top

    and

    front view

    by

  • 8/10/2019 Motorbicycle building

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    PATTERNS

    FOR

    FRAME

    CASTINGS.

    27

    Figs.

    22

    and 23. It

    may

    be made

    from

    one

    piece,

    with

    the

    prints

    for the

    central

    core and

    two oval

    cores

    glued

    and

    pegged

    on.

    It is

    4f

    in.

    over

    all,

    If

    in.

    deep

    at the

    ends,

    where the

    forks

    fit,

    and

    1^

    in.

    deep

    in

    the centre.

    The

    central

    core-print

    is l

    T

    Vin.

    in

    diameter,

    and

    the

    ovals,

    indicated

    by

    dotted

    lines

    in

    Fig.

    22,

    Ij

    in.

    by

    i

    in.

    ;

    that

    is

    the

    full

    finished

    size,

    and

    owing

    to

    the awkward-

    ness

    of

    cleaning

    out

    these

    in

    the

    casting,

    it

    will

    be

    advisable

    to

    core them out

    full

    size,

    or

    very

    Figs.

    22 and

    23. Front

    Fork

    Crown.

    nearly

    full size.

    A

    core-box

    will

    be

    necessary

    for

    this

    pattern,

    allowing

    for

    a

    uniform

    thickness

    of

    -

    in. in the

    casting,

    as shown

    by

    the

    dotted

    lines

    in

    Fig.

    23, except

    at

    the

    edges

    of the

    oval

    open-

    ings,

    which

    may

    be a

    bare

    /

    a

    -

    in. It

    will be

    noticed that

    a

    ring

    or

    collar

    is

    shown

    on

    top

    of

    the crown

    ;

    this

    is

    for the

    bottom ball-race

    to

    fit

    on.

    The

    core-prints

    need

    only project

    f

    in.,

    as

    the

    core

    will

    be

    supported

    at

    four

    points.

    Ball-head

    or

    Steering

    Tube

    Lug.

    The

    ball-

  • 8/10/2019 Motorbicycle building

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    28

    MOTOR

    BICYCLE

    BUILDING.

    head,

    or

    steering

    tube

    lug,

    is

    shown

    by

    Figs.

    24

    and

    25,

    these

    being

    side

    and

    bottom views.

    It is

    made

    by

    turning

    the

    main

    part

    to

    the

    dimensions

    given,

    allowing

    for

    machining.

    The central core-

    print

    is

    ly^in.,

    projecting f

    in. at each

    end. The

    rear

    part

    for

    the

    f-in.

    bolt

    is cut

    out

    separately,

    and

    glued

    and

    pegged

    on.

    It

    is l

    in.

    wide,

    and

    has a

    f-in.

    core-print.

    The

    two

    projections

    to

    Fig.

    25.

    Figs.

    21

    and

    2o.

    Steering

    Tube

    Lug.

    receive

    the

    ends of

    the

    girder

    tubes are cut out

    to

    shape

    as

    in

    Fig. 25,

    length

    with

    the

    grain,

    and

    the two

    lugs

    turned

    to

    shape

    and

    glued

    and

    pegged

    on.

    The

    prints

    are

    y

    7

    ^

    in.

    in

    diameter

    by

    f

    in.

    long.

    The

    two

    projecting

    pieces

    being

    so

    light

    (only

    T

    3

    (T

    in.

    thick),

    they

    should

    be dovetailed

    into

    the main

    part

    of

    the

    pattern,

    as well as

    glued

    and

    pegged,

    or

    they

    may

    soon

    be broken off

    at

    the

    foundry.

  • 8/10/2019 Motorbicycle building

    31/166

    PATTERNS

    FOR FRAME CASTINGS.

    Engine

    Plates.

    The

    pattern

    for

    the

    engine

    plates

    is shown

    by

    Figs.

    26

    and

    27,

    which

    are

    side

    and

    end

    views. Four of

    these

    plates

    will

    be

    re-

    quired.

    They

    may

    be cast in malleable

    iron

    from

    a

    pattern,

    but

    it

    is better

    to

    have

    them

    forged

    from mild steel.

    Should

    castings,

    however,

    ba

    used,

    have

    only

    the

    large

    centre

    hole

    cored,

    leav-

    ing

    the

    ends

    solid

    to be

    drilled

    out in

    the

    casting.

    Fig.

    20.

    Fig.

    27.

    Figs.

    26

    and

    27.

    Engine

    Plate.

    This

    also

    applies'

    if

    forgings

    are

    used,

    as

    the

    exact

    position

    of.

    these holes

    can

    only

    be

    ascer-

    tained

    when

    the

    frame

    is

    built

    and

    the

    engine

    tried

    in

    the

    frame,

    with

    wheels in

    position.

    Leave

    on

    Patterns.

    This

    is

    all

    the

    pattern-

    making

    that

    will

    be

    necessary,

    and

    it

    only

    re-

    mains to

    get

    the

    required

    number

    of

    castings

    made

    from

    them

    at a

    good

    malleable iron

    foundry.

    All

    parts

    of the

    patterns

    must

    be

    nicely

    smoothed off

  • 8/10/2019 Motorbicycle building

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    30

    MOTOK BICYCLE BUILDING.

    with

    fine

    glasspaper,

    leaving

    no

    rough

    edges

    or

    parts,

    and

    care

    must

    be

    observed

    to

    impart

    suffi-

    cient

    leave

    to

    the

    various

    parts

    requiring

    it.

    What

    is

    meant

    by

    leave

    on

    a

    pattern

    will

    be

    understood

    by

    taking,

    first,

    a solid ball

    and

    then

    a solid

    square

    as

    patterns.

    The ball would

    be

    moulded half

    in

    each

    moulding

    box,

    the

    parting

    taking place

    exactly

    at the centre of the

    pattern

    ;

    thus,

    as all

    parts

    of

    this

    pattern slope

    away

    from

    the

    centre

    or

    parting

    line,

    no

    leave

    would be

    necessary,

    as this

    would

    be

    a

    perfect

    form for

    leaving

    the

    sand

    well.

    But

    if a solid

    square

    or

    cube is

    taken,

    some

    part

    of

    the

    pattern

    would

    have to

    be

    tapered

    off

    to

    enable the

    pattern

    to

    come

    away

    from the sand

    without

    breaking

    down

    some

    part

    of

    the

    impression,

    unless the

    pattern

    was

    moulded

    with

    a

    corner of the

    square

    upper-

    most,

    and the

    parting

    takes

    place

    at a

    point

    which

    embraces four corners.

    Whatever

    other

    position

    this

    pattern

    might

    be moulded

    in,

    some

    portions

    of

    the

    flat

    sides

    would

    have

    to

    be

    tapered

    off from the

    parting

    line

    to enable

    it to

    leave

    properly.

    It

    is

    only

    necessary

    to

    look

    at

    a

    pat-

    tern

    carefully

    and

    imagine

    which will

    be

    the most

    convenient

    position

    to mould

    it

    in,

    to

    see

    what

    parts

    require

    leave.

    Painting

    Core-prints,

    etc.

    All

    core-prints

    should

    be

    painted

    black

    a

    little

    vegetable

    black mixed

    with

    varnish will

    do

    and

    the

    whole

    pattern

    given

    two

    coats

    of

    shellac

    varnish. This

    varnish can be

    easily

    made

    by

    dissolving

    brown shellac

    in

    methylated

    spirit, shaking

    the bottle

    frequently.

    Heat

    will

    assist

    it

    to

    dissolve,

    but

    great

    care must be

    taken,

    as

    the

    spirit

    is

    very inflammable,

    and

    likely

    to cause

    an

    accident

    if

    taken

    too

    near a

    light.

    The

    inside

    of

    the core-boxes

    should

    also

    be

    given

    two

    good

    coats

    of shellac

    varnish

    when

    finished.

    Making

    Plain

    Round

    Cores.

    For

    making

    the

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    33/166

    PATTEKNS FOR FRAME

    CASTINGS.

    31

    plain

    round

    cores,

    nothing

    beats

    cycle

    tube,

    and

    pieces

    of

    this

    to

    fit

    the

    various

    prints

    should be

    selected

    and

    cut

    to

    the

    required

    lengths.

    Where

    the

    junction

    of two

    cores

    is

    at an

    angle,

    such

    as

    the head

    lugs,

    seat

    lug,

    and lower horizontal

    tube

    lugs,

    the core tubes

    should

    be

    cut

    off at a cor-

    responding

    angle,

    and also

    hollowed out at the

    angle

    end,

    so

    that

    the

    coring

    may

    extend as

    far

    as

    possible.

    Oval Gores.

    For

    the

    oval cores

    also

    pieces

    of

    fork

    blade

    of the

    proper

    section

    will

    do

    perfectly

    for

    making

    the

    cores,

    and

    will

    save

    a

    deal

    of

    trouble

    in

    core-box

    making.

    Dowelling

    Halves

    of

    Gore-boxes. The

    two

    halves

    of

    the

    core-boxes

    for

    fork

    crowns,

    or what-

    ever core-boxes

    that are

    made

    in halves,

    should

    be fitted with two

    or

    three

    dowels

    to

    ensure

    the

    halves

    closing perfectly

    accurate

    ;

    they

    should fit

    easily,

    but

    without shake.

    Small brass

    pegs

    and

    sockets can be

    purchased

    for

    the

    purpose,

    and

    where

    the boxes

    are

    likely

    to be

    used much it

    is

    advisable

    to fit

    these,

    as

    the wood

    dowels soon

    wear

    with

    much

    usage.

    Metal

    Patterns.

    Where

    a

    large

    number of

    castings

    are

    to

    be

    made

    from

    one

    pattern,

    metal

    patterns,

    preferably brass,

    are

    made,

    and

    cast-

    iron

    core-boxes used.

    Dimensions

    on

    Illustrations.

    It

    must

    be

    borne

    in

    mind that

    all dimensions

    given

    in

    the

    illustra-

    tions

    included

    in

    this

    chapter

    are

    finished

    sizes

    of

    castings,

    and

    due

    allowance

    must be

    made

    for

    machining.

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    CHAPTER

    III.

    BUILDING FRAME

    FROM

    CASTINGS.

    HAVING

    received

    the

    castings

    from

    the

    foundry,

    free them

    well

    from

    sand

    ;

    and should

    any

    castings

    have

    become

    distorted in

    the

    annealing

    process,

    correct

    this

    by

    careful

    hammering.

    Bottom Bracket. The bottom

    bracket

    may

    first be

    taken in

    hand. Chuck

    the

    casting

    in

    a

    jaw

    chuck,

    and bore

    out

    the

    centre

    part

    ly

    7

    ^

    in. in

    diameter, leaving

    f

    in.

    at

    each

    end

    a

    full

    \^

    in.

    to

    screw

    if

    in.

    by

    24

    threads.

    Face off

    the end

    standing

    out from

    the

    chuck

    at

    this

    setting

    ;

    the

    other end

    should

    be

    faced

    off on a

    screwed mandrel

    to

    get

    perfect

    truth

    ;

    but

    if

    carefully

    chucked,

    it

    may

    be

    faced

    fairly

    true

    by

    this

    means.

    The

    bracket

    cups

    should

    be

    obtained

    or

    made

    previous

    to

    screwing

    the

    bracket,

    so

    that

    they

    may

    be

    tried

    in

    to

    fit

    before

    removing

    the

    casting

    from

    the

    chuck.

    The

    cups

    should be a

    good

    tight

    fit,

    so

    that

    they

    can

    only

    just

    be

    screwed

    up

    with

    a

    peg

    wrench. The width of

    the

    bracket when

    finished

    should

    be

    3^

    in.

    Boring

    the

    Three Tube

    Lugs.

    The best

    way

    to

    bore the three

    tube

    lugs

    will

    be

    on

    an

    angle

    plate

    or an

    upright

    drilling

    machine

    ;

    but if

    such

    a tool

    is

    not

    available,

    the

    lathe

    will

    do,

    either

    by

    bolt-

    ing

    the

    angle

    plate

    to the

    face

    plate,

    or

    by

    hold-

    ing

    the

    casting

    in the

    jaw

    chuck.

    If

    the

    latter

    method

    is

    adopted, greater

    care

    will

    be

    necessary

    in

    seeing

    that

    the

    holes

    are

    bored

    at

    perfect

    right

    angles

    to

    the

    centre bore. With

    a

    true

    angle

    plate

    and

    the

    ends

    of

    the

    casting

    faced

    true,

    this

    will

    be

    ensured.

    The

    front

    member,

    to take

    the

    tube

    from

    the

    back

    fork

    crown,

    will be

    bored

    If

  • 8/10/2019 Motorbicycle building

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    BUILDING FRAME FROM

    CARTINGS.

    33

    in.

    right through

    into

    the

    centre,

    and the

    outside

    trued

    up.

    The

    lug

    to

    take

    the down

    tube

    will now

    be

    bored

    Ij

    in.

    right

    through,

    and

    at

    an

    angle

    of

    110

    degrees

    with

    the

    first

    boring.

    The

    rear

    lug

    is

    bored

    If

    in. at

    an

    angle

    of

    64

    degrees

    with

    the

    last

    boring.

    The various

    tubes

    should

    be

    tried

    in

    their

    places

    before

    the

    casting

    is

    shifted,

    and

    should be a

    good tight

    push

    fit in

    their

    holes.

    Holes

    for

    lubricators

    should

    be

    drilled

    f

    in.

    from

    each

    face,

    in

    such

    a

    position

    that the

    lubricators

    will

    be

    upright

    when

    the bracket

    is

    in

    position.

    If

    lugs

    for

    set

    pins,

    by

    which

    the

    cups

    or

    discs

    are

    to be

    locked,

    have

    been

    provided,

    these

    should

    be

    drilled and

    tapped

    to

    suit

    the set

    pins.

    The

    dimensions

    of

    the

    disc to be used with

    lock-nuts,

    and

    also

    of

    the

    bracket

    axle,

    will

    be

    given

    later.

    Back Fork

    Crown.

    The back

    fork

    crown

    cast-

    ing

    should

    be

    chucked

    in

    the

    jaw

    chuck and

    bored

    If

    in.,

    as

    deep

    as

    possible,

    and the

    edges

    trued

    up

    ;

    or

    the

    ends of the D-section

    projections

    may

    be

    levelled

    off

    and

    the

    casting stripped

    to

    the

    face

    plate

    to bore this

    If

    in. hole.

    Whichever

    method

    is

    adopted,

    care

    must

    be

    taken

    to

    get

    the

    hole

    perfectly

    true

    with

    the

    D

    ends.

    Engine Lugs.

    The

    engine lugs

    should

    be

    chucked

    true,

    and

    the

    f-in.

    holes bored

    right

    through

    and

    reamered,

    the faces

    being

    turned

    up

    on

    a mandrel.

    They

    should

    measure

    3^

    in.

    over

    all when

    finished.

    The

    tube

    lugs

    should

    then be

    bored

    ij

    in. and

    If

    in.

    respectively,

    and

    the

    edges

    trued

    up.

    Front

    Fork

    Ends. The

    castings

    of

    the

    front

    fork

    ends

    will

    require very

    little

    machining.

    The

    f-iri.

    hole

    will

    require

    drilling,

    and

    the

    f-in.

    recess

    should

    be

    machined

    in

    the

    outside face of

    each

    with

    a

    peg

    drill

    or

    cutter.

    The

    slot

    can

    then be

    filed

    out to

    meet

    the

    f-in.

    hole.

    The

    f-in.

    lug

    to

    take

    the

    bottom

    end

    of

    the

    girder

    tube

    can

    be

    turned

    or

    filed as

    preferred.

    As

    this

    is a rather

    awkward

    casting

    to

    chuck,

    it

    may

    be advisable

    to

    c

  • 8/10/2019 Motorbicycle building

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    3i

    MOTOR BICYCLE

    BUILDING.

    file

    this

    to

    fit

    the

    tube at

    the

    same time

    as

    the

    oval

    lug

    is

    filed to fit

    the

    lower

    end

    of

    the

    oval

    fork blade.

    Whilst

    these

    are

    being

    fitted

    to their

    respective tubes, they

    should be

    tried

    on

    the

    full-

    size

    drawing

    to

    see

    that

    the

    angle

    is correct. The

    two

    stay

    eyes

    will

    require

    drilling

    out

    f

    in.

    ;

    these

    may

    be

    drilled

    at

    the

    same

    time

    as

    any

    of the

    other

    |-in.

    holes.

    Head

    Lugs.

    Chuck

    the head

    -lugs

    in

    the

    jaw

    chuck, large

    end outwards

    ;

    bore

    through

    Ij

    in.

    to

    fit

    the

    head

    tube,

    and

    turn

    out

    the

    recess

    fo,r

    ball-races,

    as

    shown

    by

    the dotted

    lines

    in

    Figs.

    15

    and 16

    (p. 23).

    These

    recesses

    will

    measure

    ^\

    in.

    at

    the extreme

    ends

    by

    ^

    in.

    deep.

    Face

    off the

    ends,

    and true

    up

    the

    outer

    edges.

    The

    Ij-in.

    tube

    members

    may

    be bored

    whilst

    held

    in

    the

    jaw

    chuck

    or

    on

    the

    angle plate,

    tilted

    to

    the

    correct

    angle

    112

    degrees

    for

    the

    top

    head

    lug

    and 56

    degrees

    for

    the

    bottom one.

    Seat

    Lug.

    Chuck

    the

    seat-lug casting

    in the

    jaw

    chuck

    to bore

    out the

    central

    lj-in.

    hole,

    with

    the

    top

    end outwards

    ;

    re-chuck

    or fix

    on

    the

    angle

    plate,

    to

    bore

    out the

    Ij-in.

    hole

    for

    the

    front

    tube.

    The

    rear

    part

    will have

    to

    be

    drilled out

    |

    in.,

    and

    ths

    ears

    faced

    off

    true

    for the

    back-stay

    eyes

    to

    bed

    against.

    The

    saw-cut should

    be

    put

    in

    the

    back,

    midway

    between

    the

    ears,

    before

    the

    lug

    is

    fitted

    and

    brazed to

    the

    seat

    tube,

    as

    the

    casting

    becomes

    very

    hard

    and

    difficult

    to

    saw

    after it

    has

    been

    brazed.

    Lower

    Horizontal Tube

    Lugs.

    The treatment

    of

    the

    lower

    horizontal

    tube

    lugs

    is

    the

    same

    as

    that of

    the

    seat

    lug

    ;

    but

    note

    should

    be

    taken

    of

    the

    difference

    in the

    angle.

    Drilling

    Girder Tube

    Stays.

    The

    |-in.

    hole

    in

    each of

    the

    girder

    tube

    stays

    may

    be

    bored

    on

    the

    drilling

    machine or

    the lathe. In

    setting

    these

    castings

    for

    boring

    the

    |-in.

    hole,

    due

    allowance

    should

    be

    made

    for

    the

    difference in

    parallel

    be-

    tween this

    and

    the

    oval

    hole. On

    reference

    to

    the

  • 8/10/2019 Motorbicycle building

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    BUILDING

    FRAME

    FROM CASTINGS

    35

    full-size

    drawing,

    it will

    be

    noticed that

    the

    girder

    tubes

    approach

    nearer

    to

    the

    centre

    steering

    line

    as

    they

    reach the

    top

    of the

    head.

    Also,

    looking

    from

    the

    front

    of

    the

    machine,

    it will be seen

    that

    the two

    tubes

    are closer

    together

    at

    the

    top

    than

    they

    are

    at

    the fork crown.

    If

    this difference

    is

    allowed

    for

    when

    drilling

    the

    f-in.

    holes,

    it will

    not

    be

    necessary

    to

    bend the

    tubes

    to

    bring

    them

    into

    place.

    Knocking

    these

    lugs

    on

    a

    f-in.

    man-

    drel,

    after

    they

    are

    drilled

    and the

    edges

    trued

    up

    in

    the

    lathe,

    will

    add

    greatly

    to

    their

    appearance.

    The

    oval holes must be filed out

    to

    fit

    the fork

    blades.

    Front Fork

    Crown.

    The front fork crown

    may

    be

    held

    in

    the

    jaw

    chuck or

    strapped

    to

    the

    face-

    plate,

    the

    centre

    hole

    bored

    1|- in.,

    and

    the

    top

    faced

    off

    and

    the

    shoulder turned

    1^

    in.

    in

    diameter

    by

    |

    in.

    deep.

    If

    the

    casting

    is

    being

    machined, strapped

    to the

    face-plate,

    this latter

    operation

    will have- to be done on a

    mandrel be-

    tween the

    centres.

    The

    oval-section

    holes

    will

    have

    to

    be

    filed

    or

    scraped

    out

    for

    the

    fork

    blades

    to fit.

    While

    the

    casting

    is

    on

    the mandrel in

    the

    lathe,

    the

    ends

    of

    the

    ovals

    may

    be

    faced

    off

    true.

    Steering-tube

    Lug Casting.

    Chuck the steer-

    ing-tube

    lug casting

    bottom or

    large

    end

    outwards,

    bore

    through

    lj

    in. to

    fit

    the

    steering

    tube

    (a

    tight

    hand

    fit),

    and

    recess out

    the

    part

    shown

    dotted

    in

    Figs.

    24

    and

    25

    (p.

    28)

    to

    take

    the

    ball-race.

    This will

    be of

    the

    same

    size

    across

    as

    the

    recesses

    in

    the

    head

    lugs,

    but

    V

    in.

    deeper,

    so

    that

    the

    edge

    of

    the-

    casting

    may

    overlap

    the

    outer

    edge

    of

    the

    top

    ball

    head

    lug

    when the two are

    brought

    together

    with

    the

    balls

    in

    place.

    This

    hides

    the

    balls,

    and

    keeps

    the

    bearing

    more

    or

    less

    dust-

    proof.

    The

    bottom

    ball

    head

    lug

    should

    be

    made

    to

    overlap

    the

    bottom

    ball-race

    on

    the

    fork

    crown

    in

    the

    same

    manner

    for

    the same

    purpose.

    At

    this

    chucking,

    the

    under side of

    the front

    ears

    may

    be

    faced,

    as

    well

    as the

    edges

    of

    the

    two

  • 8/10/2019 Motorbicycle building

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    36

    MOTOR

    BICYCLE

    BUILDING.

    girder

    tube

    lugs,

    on

    a

    mandrel

    in

    the

    lathe

    centres

    ;

    the

    outside

    and

    top

    of

    the

    casting

    may

    be

    turned

    up,

    or as much

    of

    the

    outside

    as the

    projections

    will

    allow.

    The

    ears

    should

    be drilled

    out

    |

    in.,

    and faced

    on both

    sides

    with

    a

    facing

    cutter

    ;

    the cutter

    that

    was

    used

    for

    recessing

    the

    front

    fork

    ends

    will

    do

    for

    this

    also.

    The

    two

    ^-in.

    holes

    for the

    girder

    tubes

    must now

    be

    drilled,

    and

    finished

    out

    with

    a bottoming

    drill

    or

    cutter,

    so

    that

    the holes

    have

    square

    corners or

    a

    flat

    bottom.

    A

    fine

    saw-cut

    should be

    made

    nearly

    half

    through

    the

    casting, just

    under

    the

    ears,

    as shown

    in

    Fig.

    24

    (p.

    28),

    and a

    broader

    cut

    should

    be

    run down to

    meet this

    midway

    be-

    tween

    the ears.

    Engine

    Plates.

    The

    four

    engine-plate castings

    should

    be

    levelled,

    the

    |-in.

    holes

    drilled

    square

    with

    the

    face,

    the sides

    smoothed,

    and the

    edges

    filed

    up.

    One

    of the

    |-in.

    holes in

    each

    plate may

    be

    marked

    off

    and

    drilled,

    leaving

    the other

    |-in.

    holes

    to

    be

    marked

    off and

    drilled

    after the

    frame

    is

    built

    up

    and

    the

    engine

    is in

    position.

    Ball-races.

    It

    will now

    be

    necessary

    to

    make

    the

    ball-races

    (Figs.

    28 and

    29,

    p.

    37).

    Four of

    these will

    be

    required three,

    as

    illustrated,

    for the

    steering

    tube

    lug

    and the

    top

    and bottom head

    lugs,

    and

    one

    for

    the fork crown

    ;

    this

    last

    will

    have

    square

    corners instead

    of

    round,

    and

    a

    lyV

    in.

    hole

    to

    fit

    the

    shoulder

    on

    the

    fork

    crown,

    the

    outside diameter

    being

    1^4

    in.

    These

    are

    rather

    awkward

    to

    make

    in

    an

    ordinary

    lathe

    ;

    to

    get

    them true

    they

    are

    made

    on a

    large

    hollow

    mandrel

    lathe

    from the bar.

    It would

    be

    as

    well

    to

    buy

    these

    ready-made,

    as

    they

    do

    not

    cost much. If

    it

    is

    decided

    to

    make

    them,

    good

    mild

    steel,

    well

    case-hardened,

    should

    be

    used.

    It

    would

    be

    simpler,

    in

    making

    the

    steering bearings,

    to

    dis-

    pense

    with

    cups

    or loose

    ball-races

    altogether,

    and

    turn

    the

    ball-races

    in the head and

    steering

    lugs

    themselves,

    with a steel

    cone

    only

    to

    fit on

    the

    fork

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    BUILDING

    FKAME FROM

    CASTINGS. sf

    crown.

    In

    this

    case

    the

    bearings

    should

    be

    two-

    point

    bearings,

    and

    not

    four-point,

    as

    shown

    with

    the

    loose

    ball-races.

    These

    parts

    will not

    bo

    so

    durable

    as

    well-hardened

    steel ball-races

    ;

    but

    if

    balls

    not

    less

    than

    ^'V

    in.,

    or

    T

    3

    (I

    in. for

    the

    top

    bear-

    ing

    and

    -^L

    in.

    for

    the

    bottom

    bearing,

    are

    used,

    they

    will

    wear

    very

    well.

    The malleable-iron

    castings

    become

    very

    hard when

    they

    are

    brazed,

    and

    thus

    stand a

    lot

    of

    wear.

    The

    loose

    steel

    cone on the head

    will,

    of

    course,

    be

    well

    hardened,

    and

    the

    radius of

    the

    bearing

    curves

    should not

    be much

    greater

    than the radius

    of

    the

    ball

    used,

    thus

    giving

    a

    good large

    bearing

    surface,

    instead

    of

    the

    small

    bearing

    surface

    usual with

    V-groove

    Fig.

    28.

    Fig

    29.

    Figs.

    28 and

    29.

    BalJ-race.

    bearing

    discs.

    One

    advantage

    of

    the

    absence of

    loose

    ball-race

    bearings

    is

    that there

    are

    no

    separ-

    ate

    parts

    to

    gst

    loose

    and

    cause

    play

    in

    the

    head

    Bottom

    Bracket

    Axle.

    Fig.

    30

    gives the

    full

    dimensions

    for

    the

    bottom

    bracket

    axle,

    which

    should

    be

    made,

    preferably,

    from

    one

    of Lead-

    beater

    &;

    Scott's

    patent stampings.

    These

    have

    a dead

    soft

    centre,

    which

    will not

    harden,

    with

    an

    exterior

    covering

    of

    a

    carbon

    steel

    that

    will

    harden

    direct

    in

    water,

    and

    gives

    a

    very

    hard

    wearing

    surface.

    Failing

    one

    of

    these-

    stampings,

    cast

    steel

    should be

    used,

    carefully

    hardened at-

    the

    wearing

    parts only.

    Mild

    steel,

    case-hard-

    ened,

    does

    very

    well

    for

    this

    job

    if

    proper

    facilities,

    are

    at

    hand

    for

    pot-hardening

    ;

    but

    using

    mild

  • 8/10/2019 Motorbicycle building

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    3S

    MOTOR BICYCLE BUILDING.

    steel,

    and

    attempting

    to harden

    by

    the

    ordinary

    means on

    the

    open

    hearth with

    potash,

    etc.,

    is

    quite

    useless.

    In

    making

    this

    axle,

    cut off

    the

    steel

    or

    stamping just

    the

    dead

    lengths

    required

    before

    drilling up

    the

    ends,

    so that the centres

    upon

    which

    the

    axle

    is

    turned

    may

    be

    left

    in,

    to true

    it

    up

    by

    after

    hardening.

    Fit

    the cranks

    and file

    the

    keyways

    before

    hardening.

    Special

    wide bracket

    discs

    are

    used

    with

    this

    axle,

    as

    shown

    at

    A,

    lock-

    nuts

    (Figs.

    31 and

    32)

    securing

    them.

    If it has

    been decided to

    lock

    these

    discs

    by

    set

    pins

    or

    transverse

    cotters,

    the

    ordinary

    standard

    pattern

    discs,

    which

    can

    be

    purchased

    for about

    6d.

    each,

    will

    do.

    Should lock-nuts

    for

    the

    bracket

    discs

    be

    Fig.

    30.

    Bottom Bracket

    Axle

    in

    Position.

    necessary,

    they

    may

    be

    made

    from

    ordinary

    gas

    back-nuts,

    bored

    out and

    re-screwed,

    if suitable

    stampings

    are not

    available

    ; or,

    if

    the latter are

    used,

    they

    can be made

    from

    stout 1-in.

    washers,

    bored and screwed.

    They

    need not be filed

    up

    or

    shaped hexagon ;

    but a

    couple

    of

    deep

    notches

    may

    be

    filed in their

    edge

    for

    adjustment pur-

    poses,

    as

    shown

    in

    Figs.

    31

    and

    32.

    They

    should

    be

    If

    in.

    by

    24

    threads,

    the

    same

    as

    the

    discs,

    but

    must

    be

    a

    somewhat

    easier

    fit

    on

    the

    discs

    than

    the

    discs

    are

    in

    the

    bracket,

    otherwise

    diffi-

    culty

    will

    be

    experienced

    in

    adjusting

    the

    bearing

    properly.

    At

    least

    one face

    of

    the

    nuts

    must be

    trued

    up

    with

    the thread.

    Fitting

    Lock-nut

    to

    Steering

    Tube.

    The

    steer-

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    BUILDING FRAME FROM

    CASTINGS. 39

    ing

    tube

    must be screwed

    at one

    end

    with a fine

    thread for

    |

    in. down. A

    coarser thread

    than

    26

    to

    the

    inch should

    not

    be

    used,

    otherwise

    the tube

    would

    be

    weakened

    by

    the

    depth

    of

    the

    thread.

    A

    lock-nut

    to fit

    this

    will

    be

    required,

    and

    the

    re-

    marks made

    with

    reference

    to

    the bracket lock-

    nuts

    applj

    7

    also

    to this.

    Whilst

    screwing

    the

    steer-

    ing

    tube

    and

    fitting

    the

    nut,

    pay

    attention

    to

    the

    fitting

    of

    the

    steering-tube

    lug,

    which

    must

    be

    a

    good

    sliding

    fit

    without

    shake.

    The

    saw-cut,

    which allows

    the- tube

    to

    be

    tightened

    on

    to

    the

    Fig-.

    32.

    Figs.

    31

    and

    32.

    Bracket Lock-nut,

    handle-bar

    stem,

    should

    not

    be

    made

    until

    the

    handle-bar

    has

    been

    fitted

    in

    the

    tube.

    Engine

    Bolts. Two

    f-in.

    turned

    engine

    bolts

    (Fig.

    33)

    will be

    required

    for

    securing

    the

    engine

    plates

    to their

    lugs.

    These

    are turned from

    li-in.

    mild

    steel,

    one to the

    dimensions

    given

    in

    the

    illustration,

    and

    the

    other

    \

    in.

    shorter.

    They

    should

    be

    a,

    good push

    fit,

    without

    shake,

    in the

    f-in.

    holes

    of

    the

    engine

    plates

    and

    the

    lugs

    on the

    frame.

    Building up

    Frame.

    All

    the

    lugs

    and

    parts

    having

    been machined

    ready

    for

    fitting

    up

    to

    the

    various

    tubes,

    the

    rear

    part

    of

    the frame

    may

    now

    be

    built

    up.

    Cut

    off

    the

    back

    forks

    to

    the

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    40

    MOTOR

    BICYCLE

    BUILDING.

    exact

    length

    required

    ;

    clean out

    the ends

    where

    the fork ends

    and

    fork crown

    ends

    fit

    ;

    level

    off

    the

    ends

    where

    the

    fork

    ends

    fit

    ;

    and

    chamfer

    off

    the

    inner

    edge

    of

    the

    D

    tubes,

    so

    that

    they

    fit

    neatly

    up

    to

    the

    shoulders.

    If

    these

    fit

    tight,

    they

    need not be

    pegged

    for

    brazing.

    Fit the

    top

    stay

    eyes,

    into the

    top

    back

    stays

    in a

    similar

    way.

    Cut

    a small

    notch

    in the bottom

    of

    the

    f-in.

    hole

    in

    one

    of

    these

    stay

    eyes,

    so

    that a

    small

    peg

    fitted

    under

    the head

    of

    the

    bolt,

    which

    holds the

    seat

    pillar

    tight,

    may

    engage

    with

    this

    slot

    and

    so

    prevent

    the bolt

    from

    turning

    while the

    nut

    is

    being

    tightened

    or

    undone.

    Before

    fitting up

    the

    fork

    ends

    and

    stay

    eyes,

    or

    cutting

    the tubes

    at

    all,

    see

    that

    the cranked

    portion

    of these

    comes

    in the

    proper

    position

    to

    allow

    of

    the

    belt

    rim

    clearing

    properly,

    and

    on the

    left-hand side of

    the

    machine.

    These four

    joints

    are

    then

    brazed

    and

    filed

    up.

    Setting

    Rear

    Fork

    Ends.

    The

    fork

    ends

    should

    now

    be set on

    the

    wheel.

    (The

    wheels

    should

    be made

    or

    procured

    before

    starting

    to

    build the

    frame.)

    To

    set the

    fork

    ends,

    tighten

    up

    in

    their

    place

    on

    the

    wheel

    spindle

    and

    set

    until

    the

    other

    ends of

    the

    forks

    are

    the

    proper

    distance

    apart,

    to

    correspond

    with

    the

    D-section

    ends

    of

    the

    fork

    crown,

    and

    at

    an

    equal

    distance

    from the

    edge

    of

    the

    whe-el rim.

    It

    is

    better not

    to

    set

    these* in their

    place

    on

    the

    spindle,

    or

    the

    latter

    may

    get

    bent with the strain

    ;

    they

    should

    be

    removed to the

    vice to

    be bent

    to

    the

    required

    angle.

    Brazing

    Tubes

    to

    Bottom

    Bracket.

    The two

    short

    pieces

    of

    If-in.

    tube

    may

    now

    be

    fitted

    to

    the

    bracket,

    and

    also

    the down

    tub,

    after

    thoroughly

    cleaning

    out

    the

    various

    lugs

    and

    the

    ends

    of

    the

    tubes.

    The

    ends

    of

    the

    If-in.

    tube

    that fit

    into

    the

    bracket

    should

    be

    hollowed

    out,

    to

    allow

    of

    the

    tubes

    fitting

    well

    up

    into

    the

    bracket. The

    back

    fork

    crown is then

    fitted

    to

    the other end

    of

    the

    If-in.

    tube.

    Now

    try

    this

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    BUILDING

    FRAME FROM

    CASTINGS.

    41

    part

    on

    the

    working drawing,

    and see that all

    the

    measurements

    and

    the

    angle

    of

    the down tube

    are

    correct.

    Before

    pegging

    these

    joints

    and

    braz-

    ing up,

    make

    sure

    of

    the

    following

    points

    :

    The

    down tube

    must

    be

    at

    right angles

    to the

    bore

    of

    the

    bracket

    ;

    test

    this

    with a steel

    straightedge

    on

    the

    trued-up

    faces.

    See that

    the

    back

    fork

    crown is

    square

    with

    the

    down

    tube

    ;

    test

    this

    by

    placing

    the-

    straightedge

    on

    the

    top

    of the

    D-sec-

    tion ears

    and

    sighting

    it from

    the

    back,

    when

    the

    straightedge

    should

    appear

    at

    right

    angles

    to

    the

    down

    tube. Some

    blacklead mixed

    with

    oil

    should

    be

    rubbed

    into

    the threaded

    ends

    of

    the

    bracket,

    and

    also

    into

    the

    tapped

    lubricator

    holes,

    to

    pre-

    vent

    the brass

    and borax

    adhering

    to

    these

    parts.

    Fig.

    33.

    Engine

    Plate Bolt.

    These four

    joints

    will

    require

    careful

    brazing,

    and

    a

    good

    blast

    to

    obtain sufficient

    heat. The best

    way

    to

    proceed

    is to direct

    the

    blast on

    to

    the

    heavy portion

    of the front

    lug

    ;

    get

    this

    well

    heated

    up,

    and

    make

    the

    front

    l|-in.

    joint.

    Now

    shift

    the

    flame

    on

    to

    the

    root

    of

    the

    l^-in.

    lug,

    and

    braze

    this

    joint

    ;

    then

    on to

    the

    heavy

    part

    of the

    rear

    l|-in. lug,

    and finish

    this

    joint.

    It

    will

    be advisable

    next to remove the

    job

    from

    the hearth

    and

    thoroughly

    brush

    these

    joints,

    while

    well

    hot,

    with

    the

    wire

    brazing

    brush.

    The

    joint

    of

    the

    rear

    If-in.

    tube with the

    back fork

    crown

    can then

    be

    finally

    brazed.

    Brazing

    this

    last

    joint

    will

    scale

    the

    D

    ends of

    the

    crown,

    and

    these

    must therefore be

    cleaned

    up

    again

    before

    fitting

    the

    back forks. Small air-holes

    must

    be

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    42

    MOTOR

    BICYCLE BUILDING

    drilled on

    the

    inside of

    these

    back

    forks

    before

    filing

    up

    and

    brazing.

    Other tubes

    requiring

    air-

    holes

    for

    brazing

    will

    be

    the back

    stays,

    lower

    horizontal

    tube,

    and

    front

    forks

    ;

    and

    the

    top

    tube

    and

    bottom,

    front

    tube

    as

    well,

    unless

    the

    ends

    of

    these

    are

    opened

    out

    into their

    lugs.

    When the

    back

    forks,

    exactly

    equal

    in

    length,

    are

    finally

    fitted

    to

    the

    crown,

    remove

    and

    load

    each tube

    with brass

    and

    borax,

    knock

    the

    joints

    well

    home,

    and

    peg

    securely.

    Fix

    a

    stay

    or

    strut

    between

    the

    two

    fork

    ends,

    so that

    they

    will

    be

    held

    the

    same distance

    apart

    as

    they

    will

    be

    when the

    wheel

    is in

    position.

    In

    the

    absence of

    a

    suitable

    stay,

    the hub

    spindle

    will

    do,

    the

    cones and

    nuts

    being

    used to

    keep

    the

    fork ends

    the

    correct

    dis-

    tance

    apart

    and

    the

    faces

    square with

    each

    other.

    Shake

    the

    charge, placed

    inside

    the

    tubes,

    well

    down

    towards

    the

    joints,

    and

    braze

    one

    at

    a

    time,

    with

    the fork on its

    side.

    Fitting

    Ball-head.

    Fit

    up

    the

    ball-head

    tube

    to

    the

    top

    and

    bottom

    head

    lugs,

    the

    top

    tube

    to the

    top

    head

    lug,

    and

    the

    bottom

    front tube

    to

    the

    bottom

    head

    lug,

    and

    peg

    the

    joints.

    The

    ends

    of the tubes

    should

    be hollowed out to fit

    up

    against

    the

    head

    tube.

    Before

    brazing,

    see that

    the

    three

    tubes are in

    one

    plane

    ;

    to

    test

    this,

    place

    a

    long

    straightedge

    across

    the ends

    of

    the

    top

    and bottom

    tubes,

    and

    sight

    this with

    the

    ball-

    head

    tube.

    Also

    see

    that

    the ends

    of

    the

    tubes

    are

    the

    proper

    distance

    apart

    to

    drop

    into

    place

    with

    the seat

    lug

    and

    front

    engine

    lug

    on

    the

    draw-

    ing.

    While

    these

    joints

    are

    hot,

    scrape

    out

    the

    ends

    of the ball-head

    lugs,

    where

    the

    ball

    races

    fit

    ;

    this

    will save a

    lot

    of

    work

    after,

    if

    any

    brass

    has stuck to these

    parts.

    Mark

    off,

    on

    the

    down

    and

    bottom

    tubes,

    the position

    that

    the

    Ipwer

    horizontal

    tube

    lugs

    will

    occupy,

    and

    clean

    the

    tubes

    at

    these

    parts.

    Slip

    the

    two

    lugs

    on

    to

    the

    down

    and bottom tubes

    before

    the

    seat

    lug

    or

    the

    front

    engine

    lug

    is

    fitted

    to

    its tube.

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    BUILDING

    FRAME FROM

    CASTINGS.

    43

    Fitting

    Front to Rear

    Parts.

    The seat

    lug

    can

    now

    be

    fitted to

    the

    top

    tube,

    and the

    lower

    horizontal

    tube

    to

    its

    lugs,

    and

    the

    front

    and

    rear

    portions

    of the

    frame connected

    together

    by fitting

    the

    seat

    lug

    on

    to

    the

    top

    of the

    down

    tube.

    In

    fitting

    this

    front

    portion

    to

    the

    rear

    part,

    see

    that all

    the

    tubes

    lie

    in one

    plane

    before

    pegging

    up.

    To test

    this,

    place

    a

    long

    straightedge

    across

    each

    side

    of

    the ball-head

    and down

    tubes

    ;

    the end

    of

    this should

    fall

    at

    an

    equal

    distance

    from each

    fork-end face.

    The

    ball-head

    tube

    must also

    be

    perfectly parallel

    with

    the

    down tube.

    These

    three

    joints

    may

    now

    be brazed

    up.

    The

    top

    tube

    is

    opened

    out into the seat

    lug

    by punch-

    ing

    a

    hole

    through

    the down

    tube

    inside the

    seat

    lug.

    This

    will

    act

    as

    an

    air

    hole,

    and

    serve

    as

    a

    means

    of

    feeding

    a

    charge

    of brass and

    borax

    to

    the

    joint.

    The

    lower horizontal

    tube

    lug

    joints

    may

    be

    fed

    by ramming

    a

    piece

    of

    paper

    down the

    tube,

    about

    the

    centre,

    before

    fitting

    up

    ;

    a

    charge

    can then be

    inserted

    at

    each end

    of the

    tube,

    the

    paper

    keeping

    them

    apart.

    Fitting

    Top

    Back Stays.

    The

    top

    back

    stays

    may

    now

    be

    fitted

    and brazed

    up.

    Before

    pegging

    up

    these

    two

    joints,

    the

    wheel

    must

    be

    tried

    in

    place,

    and

    the

    stays

    so

    fitted

    that

    the

    rim of the

    wheel

    is

    exactly

    central between

    them.

    Fit

    the

    mud-guard

    stay,

    and braze in

    place,

    to

    give

    1^-in.

    clearance between

    the

    mudguard

    and the

    tyre.

    The

    fitting

    and

    brazing

    of the

    engine

    lugs

    had

    better

    be

    left

    until

    the

    front forks

    are built

    and

    the

    engine

    is

    ready.

    Fitting

    Front

    Forks.

    Now

    the front

    forks

    may

    be

    secured.

    Fit and

    braze the

    steering

    tube

    to

    the

    fork crown

    ;

    then

    square

    off

    the

    bottom ends

    of

    the

    front

    forks

    and

    clean

    out

    all

    scale,

    and

    serve

    the

    lower ends

    of

    the

    girder

    tubes in the

    same

    way.

    Fit

    the

    fork

    ends to the

    fork

    blades,

    set

    in

    the same manner as the rear

    fork

    ends

    on

    the front

    wheel,

    and braze

    up

    these two

    joints.

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    44

    MOTOR

    BICYCLE

    BUILDING.

    Next

    cut

    off the

    top

    ends

    of the

    blades to

    the

    proper

    length,

    to

    give

    the

    required

    clearance to

    the

    tyre

    under

    the

    fork

    crown.

    Clean

    the

    ends

    of

    the

    blades

    outside

    sufficiently

    far

    down

    to

    allow

    for the

    girder

    tube

    stays,

    then

    slip

    these

    stays

    on

    over the

    fork

    blades,

    load each

    with

    brass

    and

    borax,

    and fit

    into the

    crown,

    taking

    care to

    knock

    them

    well

    home.

    The

    two blades

    should be

    of

    exactly

    the same

    length,

    and,

    after

    being

    tested,

    should

    be

    fixed

    at

    an

    equal

    angle

    to

    the

    steering

    tube when the ends

    are

    the

    proper

    distance

    apart.

    Fit the

    wheel

    in

    the

    forks,

    and

    see

    that

    the

    rim

    is

    central

    between

    them,

    and use

    the

    straightedge

    to see

    that

    the

    steering

    tube is

    true

    with

    the wheel

    rim.

    When

    this is

    all

    as-

    sured,

    fix

    the

    wheel

    spindle

    or other stay

    between

    the fork

    ends,

    and

    peg

    and

    braze

    up

    the

    four

    joints.

    The

    f-in.

    holes

    of the

    girder

    tube

    stays

    must

    now

    be cleaned

    out,

    the tubes where

    they

    fit

    these,

    and

    the

    inside

    of

    the

    lower

    ends,

    to fit

    on

    the

    front

    lug

    of

    the

    fork

    ends.

    The exact

    length

    of

    these

    two

    girder

    tubes

    is

    obtained

    by

    assembling

    the

    ball-head

    with

    balls

    and

    races

    in

    position.

    It is

    very important

    that the

    length

    of

    these

    shall be

    absolutely exact,

    for

    if

    they

    are

    the

    least

    bit

    too

    long,

    the ends would bottom

    in

    the holes

    of

    the

    lugs

    on

    front

    of

    the

    steering-tube

    lug

    before the

    bearing

    was

    properly

    adjusted.

    The

    tubes should

    be

    of

    such

    a

    length

    as

    to

    be

    about

    ~

    in.

    off

    the

    bottom

    of

    the

    holes,

    when the

    bearing

    is

    tightly

    adjusted.

    This

    allows

    for

    subsequent

    wear

    and

    adjustment

    of

    the head

    bearings.

    Of

    course,

    it-

    is

    understood that

    the

    tops

    of

    these

    tubes are not

    brazed

    into

    the

    lugs,

    but

    are

    a

    good

    tight sliding

    fit

    in

    them.

    When

    the

    proper

    length

    has been

    obtained,

    take

    down

    the

    head and

    braze the

    four

    joints

    at

    the crown

    and

    lower

    ends.

    It will

    be as well

    to

    slip

    the

    steering

    tube

    lug

    on

    to

    the

    top

    ends of

    the

    girder

    tubes

    while these

    four

    joints

    are

    being

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    BUILDING

    FRAME

    FROM CASTINGS.

    45

    brazed,

    thus

    ensuring

    them

    being

    the exact

    dis-

    tance

    apart

    to

    drop

    afterwards

    into their

    places.

    Before

    filing

    up

    the

    fork

    joints*

    try

    the

    front

    wheel

    again,

    to see

    if

    any

    part

    has

    sprung

    or

    given,

    and

    thus thrown

    the

    wheel

    out

    of

    centre.

    It

    will,

    of

    course,

    be

    better

    to correct this

    now

    than

    to

    wait

    until after

    the

    joints

    are

    filed

    up.

    While

    the wheel

    is

    in

    the

    fork,

    both before and

    after

    brazing,

    place

    the

    straightedge

    across

    the

    front

    of

    the

    fork

    crown,

    and

    see

    that

    is is

    parallel

    with

    the

    wheel

    spindle.

    Should

    the fork

    be

    on

    the

    twist,

    this

    can be rectified

    by

    holding

    the

    crown

    in the vice and

    inserting

    a bar between

    the

    lower

    end

    of

    the

    fork

    blades.

    Handle-bar and

    Seat

    Pillar.

    The

    handle-bar

    and seat

    pillar

    call

    for no

    special

    mention,

    ex-

    cept

    that

    they

    are

    stronger

    than

    the

    ordinary

    cycle

    type,

    and that

    the

    handle-bar

    is

    wider and

    longer,

    as

    already

    mentioned. The

    stem

    of both

    the

    seat

    pillar

    and the handle-bar

    should

    be fitted

    into

    their

    respective

    tubes before the saw-cut is

    made

    down

    them.

    Fitting

    Engine

    Plates.

    If

    the

    engine,

    or

    the

    crank

    case

    of

    the

    engine,

    is

    now

    available,

    the

    four

    engine

    plates

    can

    be fitted to

    the crank case.

    The

    pair

    on

    the

    pulley

    side will

    be

    let

    in

    flush

    with

    the surface of

    the crank

    case,

    so

    as to

    give

    clearance to

    the belt.

    With the

    engine

    lugs

    slipped

    on

    to

    the

    ends

    of

    the

    bottom

    down

    tube

    and

    the

    short

    l--in.

    tube,

    the

    proper

    position

    for

    the

    f-in.

    holes

    in the

    engine

    plates

    and

    the correct

    position

    of

    the

    engine

    lugs

    on

    the

    tubes

    can

    be

    marked

    off

    to

    bring

    the

    engine

    square

    and

    per-

    pendicular

    in

    the

    frame.

    The

    two

    lugs

    should

    be

    pegged

    on

    the

    tubes

    while

    the crank

    case

    and

    plates

    are

    in

    position

    with

    alj

    bolts

    in,

    to ensure

    their

    coming

    together

    again

    properly

    when

    brazed

    up.

    It

    will

    be

    advisable to

    blacklead

    the inside

    of

    the

    f-in.

    holes

    in

    the

    engine

    lugs

    before

    brazing

    to

    prevent

    them

    scaling

    or

    getting

    brass

    on

    them.

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    47

    CHAPTER

    IV.

    MAKING

    A

    3i-H.P.

    PETROL

    MOTOR.

    THE motor

    to

    be

    described

    in

    this

    chapter

    will

    develop

    3i

    h.p.,

    and is suitable

    for

    the

    frame

    described

    in

    the

    previous

    chapters.

    It

    is

    quite

    powerful

    enough

    for use

    with

    a

    trailer, side,

    or

    fore

    car. With a

    two-speed

    gear,

    it

    may

    also

    be

    used

    for

    a

    tri-car.

    This

    is

    not

    an

    experimental

    engine,

    but one

    that has

    been

    made

    and well

    tried

    over

    some

    thousands of

    miles,

    giving

    every

    satis-

    faction.

    It

    is

    of

    original

    design

    and

    simply

    con-

    structed

    with

    as few

    parts

    as

    possible

    (see

    the

    vertical

    'section,

    Fig.

    34,

    in

    which

    the

    valve

    springs

    are

    not

    shown).

    The

    patterns

    for all the

    parts

    are

    finished,

    and are

    available

    to

    readers of

    this

    handbook

    who would like

    to

    purchase

    the

    castings

    instead

    of

    making

    their

    own

    patterns,

    so

    that

    an immediate

    start

    could

    be

    made.

    The

    cylinder

    pattern

    is

    an

    exceedingly

    difficult one

    for an amateur

    to

    make

    ;

    in

    fact,

    it

    is

    the work of

    a first-class

    pattern-maker

    to turn

    out

    a

    good

    working

    pattern.

    Fig.

    35

    is

    a

    section

    of

    the

    cylinder

    through

    the

    line

    x x

    in

    Fig.

    36,

    which

    is

    a

    plan

    of

    the

    top.

    Fig.

    37

    is

    a

    plan

    of

    the

    bottom

    or

    open

    end

    of

    the

    cylinder.

    Boring

    Cylinder.

    The

    first and most im-

    portant part

    to

    be taken

    in

    hand

    is

    the

    cylinder.

    The

    boring

    and

    machining

    of

    this

    calls

    for

    the

    greatest

    care

    and

    skill

    to

    obtain

    really good

    re-

    sults.

    The

    cylinder,

    etc.,

    being

    all

    in

    one cast-

    ing,

    increases the

    difficulty

    of

    accurate

    boring,

    but

    makes

    a

    much

    more

    satisfactory

    job

    when

    finished.

    Before

    starting

    the

    boring operation,

    the

    casting

    should

    be

    carefully

    examined

    for

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    MOTOR

    BICYCLE

    BUILDING.

    Fig.

    34. Vertical

    Section

    of

    3|-h.p.

    Petrol

    Engine.

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    MAKING A

    3A-H.P.

    PETROL

    MOTOR.

    4

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    50

    MOTOR

    BICYCLE BUILDING.

    carefully

    chipped

    'off.

    The

    open

    end should

    be

    filed

    level,

    and a

    piece

    of hardwood

    fixed across

    the

    open

    end.

    From

    a centre

    marjked

    on

    this

    hardwood

    the

    size

    of bore can be

    scribed off

    and

    lightly

    centre-dotted.

    The bore

    is

    82

    mm.,

    or

    approximately

    ^

    T

    in. under 3

    in.

    ;

    and the

    stroke

    is

    3^

    in.

    In

    outlining

    the

    bore,

    it

    is

    advisable

    to mark

    just

    outside

    the exact

    bore,

    so that the

    boring

    will

    not

    completely

    obliterate

    the

    marks.

    There

    is a

    small boss on the

    top

    of the

    cylinder;

    this boss is

    perfectly

    central

    with

    the

    cylinder

    walls,

    and is

    placed

    there

    to

    assist

    in

    setting

    the

    casting

    true

    for

    boring,

    and

    to take

    the centre

    for

    turning

    up

    the outside below the

    radiators.

    The boss should be

    carefully

    centred,

    and

    drilled

    up

    with

    a

    small

    hole,

    and

    countersunk

    to

    the

    same

    angle

    as

    the lathe centres. Another

    use for this

    boss

    is

    to time the

    valves,

    by

    passing

    a

    wire

    down

    a

    hole

    drilled

    right through

    and afterwards

    stopped

    up

    with

    a

    small screw.

    The

    casting

    may

    be

    strapped

    to the

    face

    plate,

    and

    bored

    up

    with a tool

    in

    the slide-rest

    or

    strapped

    down

    to

    the

    saddle

    and

    bored with

    a

    stiff

    boring

    bar held in a

    firm,

    solid

    chuck.

    By

    the first

    method, cylinders may

    sometimes

    be

    bored

    accurately,

    but the

    chances

    are

    against

    it.

    The

    latter method

    will

    be more

    satisfactory.

    A

    good

    stiff

    boring

    bar,

    not

    less

    than

    li in.

    in

    diameter

    and

    no

    longer

    than

    absolutely

    neces-

    sary,

    should

    be used.

    This should be fitted

    with

    a

    flat cutter

    made

    from

    l|-in.

    by

    j-in.

    steel,

    double

    cutting,

    the corners

    being

    rounded

    off

    and

    the

    cutting edges slightly

    backed off.

    Three

    cutters

    are

    required,

    a

    roughing,

    second,

    and

    finishing,

    the last

    being

    only

    slightly

    rounded

    on the

    corners

    and

    the

    cutting

    edges

    finely

    finished

    off

    on

    the

    oil-

    stone to

    the size of

    the bore

    that

    is,

    82 mm.

    The

    cutter must

    run

    dead

    true

    in

    the

    lathe,

    or the

    bore

    will

    be

    greater

    than

    the

    width

    of

    the

    cutter.

    Three cuts should

    be

    sufficient,

    the

    finish-

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    MAKING A

    3i-H.P. PETROL

    MOTOR.

    ol

    ing

    one

    being

    a mere

    scrape.

    During

    the

    finishing

    cut

    and

    the one

    before

    it,

    the

    lathe

    must

    not

    be

    stopped

    from

    the

    commencement

    to

    the

    finish

    of

    the

    cut.

    The

    job

    may

    be done

    with one

    cutter,

    one

    end

    only

    cutting,

    and the cutter

    adjusted

    farther

    out

    for

    each

    cut;

    but

    it

    should be

    freshly

    sharpened

    for the

    finishing

    cut. A

    single-ended

    cutter

    is

    more liable

    to

    spring

    and follow

    in-

    equalities

    in the

    casting

    than

    a

    double-ended

    one,

    and

    for

    this

    reason

    at

    least

    one

    extra

    cut

    should be

    employed

    in

    the

    operation.

    The

    casting

    must

    be

    very carefully

    set,

    and

    Fig.

    37.

    Plan

    of

    Bottom or

    Open

    End

    of

    Cylinder.

    bolted

    down with

    good

    broad

    straps,

    one

    strap

    coming

    across the thick

    part

    of the

    valve

    cham-

    ber and

    the other

    across

    the

    flange

    at

    the bottom.

    Secured in this

    manner the

    casting

    is less

    liable

    to

    be

    sprung

    out

    of

    shape.

    The

    cylinder

    walls

    being

    only

    ^\

    in. thick

    (finished),

    no

    allowance

    can

    be made for

    any

    inaccuracy

    in

    setting.

    The

    small

    lug

    on

    top

    of

    the

    cylinder

    will

    here be found

    useful,

    as the

    back

    centre

    of

    the

    lathe can

    be

    brought

    up

    close

    to

    the

    casting

    and

    used

    to

    test

    the

    accuracy

    of

    this end

    ;

    the

    open end,

    of

    course,

    can

    be

    more

    easily

    set

    by

    the

    cutter

    edges.

    The

    cutter

    slot

    in

    the

    boring

    bar

    should

    be

    within

    -4

    in.

    of

    the

    end,

    to avoid

    any

    risk

    of

    the

    end

    of

    the

    bar

    coming

    in

    contact

    with

    the

    cylinder

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    62

    MOTOR BICYCLE BUILDING.

    end

    and thus

    shifting

    the

    setting;

    this

    would be

    disastrous

    in

    the

    finishing

    cut

    or the

    one before

    it.

    It will

    be

    noticed

    that the last

    f

    in.

    of

    tne

    cylinder

    is

    shown counter-bored.

    It will

    not

    be

    necessary

    to

    bore

    this

    part

    if

    the

    casting

    is

    accurately

    set,

    as the

    casting

    is

    cored

    out at

    this

    part

    y

    1

    ^

    in.

    larger

    than

    the

    finished bore.

    Machining

    Chamfer

    at

    Mouth

    of Cylinder.

    At

    this

    setting,

    after

    the

    bore

    is

    finished,

    the

    chamfer

    at

    the

    mouth

    of

    the

    cylinder

    should be

    machined.

    This can

    be

    done

    with a

    separate

    cutter,

    or a

    corner of

    the back

    portion

    of on-e used

    for

    boring

    may

    be filed

    to

    the

    necessary

    shape.

    This

    chamfer

    is

    necessary

    for

    the

    easy

    insertion

    of

    the

    piston

    when

    the-

    rings

    are

    in

    position.

    The

    extreme

    end

    may

    also

    be

    trued

    up

    with

    the

    cutter

    at this

    setting.

    This

    should be done to

    allow

    of

    the

    under

    part

    of

    the

    flange

    being

    -^

    in.

    from the

    end

    and

    the

    cylinder

    6|

    in.

    deep.

    To machine the

    valve

    chamber,

    the

    casting

    should

    be

    firmly

    bolted

    down

    to

    a

    perfectly

    true

    face

    plate,

    2|

    in.

    out

    of

    the

    centre,

    to

    get

    the

    opening

    true.

    As

    the

    sur-

    face

    in

    contact

    with

    the

    face-

    plate

    is

    so

    small,

    the

    casting

    is

    liable

    to

    shift

    during machining

    unless

    it

    is

    very

    firmly

    bolted

    down.

    A

    sheet

    of brown

    paper

    placed

    between

    the

    face

    plate

    and the

    mouth

    of

    the

    casting

    will

    greatly

    assist

    in

    keeping

    it

    from

    shifting.

    Valve

    Seating,

    Opening,

    etc.

    When

    set

    true,

    bore

    out

    and

    screw

    the

    exhaust-valve

    guide

    holes

    A

    (Fig.

    35)

    to

    f-in.

    whitworth. With

    a hook

    tool,

    face the

    under

    side

    of

    this

    hole

    for

    the collar

    on

    the

    guide

    to bed

    true

    against

    ;

    this collar

    will be

    1

    T

    V

    in.

    in

    diameter.

    The

    seating

    for

    the

    exhaust

    valve

    will

    be

    bored

    out

    If

    in.,

    the

    upper

    side

    being

    chamfered

    as

    shown

    and

    the

    top

    trued

    up.

    The

    opening

    for

    the inlet

    valve

    is

    bored out

    lj in.,

    and

    chamfered

    the

    same

    as

    the exhaust

    opening

    ;

    \

    in.

    above this

    bore

    out

    If

    in.

    ;

    the

    remaining portion

    B

    (|

    in.)

    is

    bored

    1

    T

    ^

    in.

    bare,

    and

    screwed 20

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    MAKING

    A

    3A-II.P.

    PETROL

    MOTOR. 53

    threads

    to

    the

    inch,

    which will

    make

    it

    If

    in.

    at the

    bottom

    of

    the

    thread.

    Face

    off

    the

    top

    of

    the

    opening

    true

    to

    the

    dimensions

    given.

    Turning

    up

    Outside

    of

    Cylinder.

    To

    turn

    up

    the outside

    of

    the

    cylinder

    below the

    radiators,

    the

    casting

    should

    be

    run on

    the

    centres. For

    this,

    a

    large

    centre

    to fit

    the

    back

    poppet

    of

    the

    lathe

    must

    be

    made,

    or

    the

    mouth

    of

    the

    cylinder

    may

    be bridged

    with

    a

    stout

    piece

    of

    iron

    or

    steel

    carefully

    fitted to

    the

    bore

    and

    centred

    true. The

    outside between

    the

    lower

    radiator

    and

    the

    top

    of

    the

    flange

    is turned to

    3

    T

    7

    ^in.,

    the

    flange

    being

    left

    $

    in.

    thick,

    and

    the

    shoulder

    3j

    in.

    in

    diameter

    by

    -j^

    in.

    deep

    ;

    this

    shoulder should be

    left

    with a

    very

    slight

    taper

    on

    it,

    so

    that

    it

    may

    fit

    tight

    into

    the

    opening

    in the

    top

    of

    the

    crank

    case.

    Opening for

    Exhaust

    Pipe,

    etc.

    The

    opening

    for

    the exhaust

    pipe,

    which

    is

    indicated

    by

    the

    dotted

    circle

    c

    (Fig.

    1)

    in

    the

    centre

    of

    the

    valve

    chamber,

    must

    now

    be-

    drilled

    and

    tapped.

    This

    is

    lj

    in.

    by

    26

    threads,

    and is best

    done

    on the

    drilling

    machine,

    using

    a

    suitable

    tap

    to

    form the

    thread,

    as

    it

    is rather

    awkward

    to chuck or

    hold

    in

    the

    lathe.

    The

    sparking-plug

    hole

    D

    is drilled

    and

    tapped

    |~J

    in.

    by

    17

    threads,

    and is faced

    on

    the

    outer

    surface.

    Flange

    on

    Cylinder

    Bottom. The

    flange

    on

    the

    cylinder

    bottom

    is left the

    full

    size

    at

    present,

    being

    filed

    off

    flush

    with

    the flange

    on

    the

    top

    of

    the

    crank case after

    the

    two

    parts

    are

    fitted

    to-

    gether.

    Holes

    for

    Holding-down

    Bolts.

    The

    four

    f-in.

    holes for

    the

    holding-down

    bolts,

    shown

    in

    the

    plan

    of

    the

    bottom

    end at

    Fig.

    3,

    should

    be

    drilled

    in

    such

    a

    position

    as

    to

    Leave

    an

    equal

    amount of

    metal

    round

    the

    corresponding

    holes

    in

    the

    crank

    case,

    but

    keeping

    the

    holes

    sufficiently

    far from

    the

    outer

    face of the

    cylinder

    to enable

    the corners

    of

    the

    bolt

    heads

    to clear

    properly.

    Piston. The

    piston

    casting

    should now

    be

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    54

    MOTOR

    BJCYCLE

    BUILDING.

    trimmed

    up by

    filing

    or

    carefully

    chipping

    off

    all

    rough projections

    left

    from

    the

    foundry.

    The

    cast-

    ing

    should be chucked

    by

    the

    projection

    left

    on

    the

    end

    of

    the

    casting,

    in

    a

    3-jaw

    or

    4-jaw chuck,

    and

    should

    not

    be

    shifted

    until

    all

    the

    turned

    work

    is

    finished.

    In

    setting

    the

    casting,

    true

    up

    from

    the

    inside,

    for

    unless the inside is

    true the

    piston

    will

    be

    very

    thin

    on

    one

    side

    when

    finished,

    as

    the

    walls

    will

    be

    rather

    light

    in

    parts.

    Turn

    up

    the

    outside

    perfectly

    parallel

    from end

    to

    end,

    82

    mm.

    in

    diameter;

    it should

    be

    a

    fairly

    easy

    fit

    in

    the

    cylinder

    at this

    stage.

    Turn

    as

    near

    the

    size

    as

    possible

    with

    a

    light

    finishing

    cut,

    and

    smooth off

    to

    the

    final

    fitting

    with

    a dead smooth file. True

    up

    the

    open

    end,

    and

    with

    a

    good

    sharp

    parting

    tool

    cut

    down

    the

    head

    to

    the

    projection by

    which

    the

    casting

    is

    held,

    leaving

    it

    3j

    in.

    long

    from end

    to

    end.

    Ring

    Grooves in Piston.

    The

    ring

    grooves

    may

    now

    be

    put

    in

    ;

    these

    are

    y^-

    in.

    wide

    by |

    in.

    deep,

    and

    are

    g

    in.

    apart,

    the first or

    top

    one

    starting

    J

    in.

    from

    the

    end.

    The

    tool

    with

    which

    these'

    are cut

    must

    be

    carefully

    made

    and

    set,

    so

    as

    to

    leave the sides

    perfectly square

    and

    the

    corners

    sharp.

    A

    tool

    made as a

    parting

    tool,

    jusb

    yV

    i

    n

    -

    wide,

    with

    the sides

    slightly

    backed

    off,

    will

    do

    the

    job

    at

    one

    cut,

    and ensure them

    being

    all the same width

    ;

    but

    unless

    the

    lathe

    is

    a

    good

    solid

    tool,

    free from

    spring,

    the

    yV^

    n

    -

    cu

    ^

    may

    be

    too

    much for

    it

    and

    set

    up

    chattering.

    In this

    case,

    a

    narrower

    tool

    must

    be

    made,

    not

    more

    than

    g

    in.

    wide.

    Whichever

    way

    the

    job

    is

    done,

    the sides of

    the

    grooves

    must

    be

    perfectly

    parallel

    and

    square.

    A

    small

    sheet-metal

    template

    should

    be

    filed

    out for

    the

    purpose

    of

    testing

    them

    for

    depth

    and

    width.

    Gudfjeon-pin

    Hole. At a distance

    of

    lj

    in.

    from

    the

    top

    end,

    scribe a

    line

    round

    the

    piston

    with

    a

    sharp-pointed

    tool

    held in

    the

    slide-rest